MINNEAPOLIS - A Minnesota National Guard member has been charged with fraud after FBI agents said they learned he had stolen personal information on 400 soldiers from his former Army unit, and a federal judge has ordered him held temporarily in jail.

Investigators suspect the defendant, Specialist Keith Michael Novak, planned to sell the information for profit and to use it to create false identities for himself and militia members who may need to escape the law.

A defense lawyer for Novak could not be reached immediately for comment on the charge and the detention order entered Wednesday and filed on electronic court records Thursday.

Novak, a suspected militia commander who is assigned as a human intelligence analyst in the Minnesota Guard, is accused of taking personal information including Social Security numbers, birth dates and ranks while he was on active duty in the Army assigned to the 82nd Airborne Division before he joined the Minnesota Army National Guard in September 2012.

U.S. Magistrate Judge Franklin Noel ordered Novak held after an initial appearance Wednesday in federal court in Minneapolis. He is scheduled to return to court on Monday for a full detention hearing that will determine whether he will have to remain in custody pending trial.

An affidavit in support of the criminal complaint against Novak says he prepared to fight if authorities tried to arrest him, readying rucksacks for a barricade at his apartment and 5,000 rounds of ammunition.

"I've my AK in my bed. If I hear that door kick, it's going boom, boom, boom, boom, boom, boom...," Novak said in a recorded conversation excerpted in the affidavit.

Novak was in guard training in Utah earlier this year when he met two men who told him they were members of a Utah militia group, FBI Special Agent Marc Rensch said in the affidavit filed with the federal complaint. Those men were really undercover FBI employees, he said.

Novak met with the men several times, telling them in a July meeting at his apartment in a St. Paul suburb that he had the soldiers' personal identification that could be used to make fake identification, the affidavit said.

Novak told them he had stashed weapons around the state if he needed to flee the apartment and told another person he had taken flak vests, camouflage netting and riot gear from the Army, the affidavit said.

Novak emailed personal identification information on seven soldiers in late September, the affidavit said. Five days later, the undercover employees attending a field training exercise in rural Minnesota with Novak and his militia members.

Novak sent an encrypted email with 44 soldiers identity information in November, according to the affidavit.

The Minnesota Guard is aware of the charges and cooperating with the FBI's investigation, Lieutenant Colonel Kevin Olson, a guard spokesman, said in a statement.